Technical Field
The present disclosure relates generally to the field of combustion burners, combustion burner panels, and methods of use, and more specifically to burners, burner panels, submerged combustion melters, and methods of their use, particularly for melting glass-forming materials, mineral wool forming materials, rock wool forming materials, and other non-metallic inorganic materials.
Background Art
A submerged combustion melter (SCM) may be employed to melt glass batch and/or waste glass materials to produce molten glass, or may melt mineral wool feedstock to make mineral or rock wool, by passing oxygen, oxygen-enriched mixtures, or air along with a liquid, gaseous and/or particulate fuel (some of which may be in one or more of the feedstock materials), directly into a molten pool of glass or other material, usually through burners submerged in a turbulent melt pool. The introduction of high flow rates of products of combustion of the oxidant and fuel into the molten material, and the expansion of the gases during submerged combustion (SC), cause rapid melting of the feedstock and much turbulence and foaming.
In the context of SCMs, SC burners are predominately water-cooled, nozzle mix designs and may avoid premixing of oxidant and fuel for safety reasons due to the increased reactivity of using oxygen or oxygen-enriched oxidants as the oxidant versus air. Nevertheless, certain submerged combustion burners employ a smooth exterior surface, half-toroid metallic burner tip of the same or similar material as the remainder of the burner, where the fuel and oxidant begin mixing just after escaping the burner tip. When using such burners in an SCM for the manufacture of glass or other molten materials, the burner tip is placed in an extreme environment. The burner tip may be exposed to corrosive oxidants, fuels, and/or combustion products, high temperature direct contact with molten and/or unmelted materials (unmelted materials may be very abrasive to metal burner components and refractory linings of an SCM), internal pressure from water or other coolant, vaporization of coolant within the burner tip, thermal cycling, and the like. As a result, great engineering and design effort has been expended designing half-toroid metallic burner tips of the same or similar material as the remainder of the burner having thermal fatigue resistance, high melting point, high temperature corrosion/oxidation resistance, high temperature structural strength, and with ease of ability to join to the remainder of the burner.
Due to these requirements, noble metal (sometimes referred to as precious metal) alloys have become the focus for half-toroid metallic burner tips and other burner components. However, being expensive alloys, it is not presently economical to fabricate the entire burner using these materials. Because of this, up until now the burner designer was left with the challenge of determining how to best attach the non-noble metal portion of the burner to the noble metal tip without sacrificing other concerns, such as good mechanical strength, coolant leak proofing, and noble metal recovery. It would be an advanced in the submerged combustion melter art to avoid some or all of these issues, and prolong the run-length or campaign length of submerged combustion melters.